The present invention relates to a diene rubber composition comprising, preferably in major part, alumina as reinforcing filler, which can be employed for the manufacture of tires.
With the aim of reducing fuel consumption and the pollutants emitted by motor vehicles, great efforts have been made by tire designers to produce tires which exhibit at the same time a very low rolling resistance, improved adherence both to dry ground and to wet or snow-covered ground and very good resistance to wear.
Many solutions have been proposed for lowering the rolling resistance and improving the adherence of tires, but they are generally reflected in a very considerable loss of abrasion resistance. It is well known, in fact, to a person skilled in the art that the incorporation of conventional white fillers such as silica, alumina, bentonite, clay, kaolin, chalk, titanium oxide, talc, and the like into rubber compositions employed in the manufacture of tires and especially of treads, is undoubtedly reflected in a lowering of the rolling resistance and in an improvement in the adherence to wet, snow-covered or glare-iced ground, but also in an unacceptable loss in resistance to wear.
An effective solution to this problem has been described in Patent Application EP-A-0 501 227, which describes a sulfur-vulcanizable diene rubber composition obtained by thermomechanical working of a copolymer of a conjugated diene and of an aromatic vinyl compound prepared by solution polymerization with 30 to 150 parts by weight per 100 parts of elastomer of a specific highly dispersible precipitated silica.
Other compositions possessing such an excellent compromise between a number of contradictory properties would be of major interest to tire manufacturers who would thus have various methods of operation at their disposal. In addition, the improvement in the resistance to wear thus obtained could optionally be converted into lowering of the rolling resistance by decreasing the tread thickness. Manufacture of tires exhibiting an unaltered lifetime, but lighter and therefore consuming less energy, could thus be envisaged.